1. Field of the Invention
The present invention relates to an apparatus and method for fabricating a lenticular plate, more specifically, to an apparatus and method for fabricating a lenticular plate by irradiating with laser light a plate to which a photosensitive material has been deposited.
2. Description of the Related Art
A lenticular plate, also known as a relief lens raster screen, is a plate on which cylindrically symmetric relief lenses of diameters ranging from several hundred .mu.m to several mm are arranged. In general, the lenticular plate is used as a screen for displaying three-dimensional images or multi-view pictures or used as a transmission diffraction grating for diffracting light into a particular direction. An apparatus for displaying three-dimensional images by means of a lenticular plate is described in "Lenticular 3-D Display" at pages 341-347 of Compilation of Next Generation Optical Technology, published by Ohutoroniwasu, Co., Japan.
In a conventional method for fabricating a lenticular plate, described in Japanese Laid-Open Patent Publication No. hei4-135744 for "A Method for Manufacturing Packaging Material of Diffraction Grating," a master plate for the lenticular plate is formed by engraving rows of cylindrically symmetric lens shapes having desired parameters on a metal (e.g., bronze) plate and the lenticular plate is formed by compressing a layer of a plastic, such as acryl or poly chlorovinyl, against the master plate, which functions as a mold. According to this method, however, a new master plate must be formed whenever the characteristics of the lenticular plate is changed. It is also difficult to form lens shapes having different parameters on a single master plate.
According to another conventional method for fabricating a lenticular plate, described in Russian Patent Publication No. SU-1817579 by Ivlyushkin A. N., 1996, a glass plate onto which a layer of dichromated gelatin (DCG) has been deposited is exposed to an infrared light through a mask having parallel slits. The DCG hardens in proportion to the time-integrated intensity of the light absorbed. The shortcoming of this method is that the DCG layers must be coated and developed two times on the same glass plate. Moreover, a new mask must be formed whenever the characteristics of a lenticular plate are changed.